Environmental Sciences

The Sagebrush Steppe Treatment Evaluation Project (SageSTEP) is an integrated long-term study that evaluates ecological effects of alternative treatments designed to reduce woody fuels and to stimulate the herbaceous understory of sagebrush steppe communities of the Intermountain West. This synopsis summarizes results through 3 yr posttreatment. Woody vegetation reduction by prescribed fire, mechanical treatments, or herbicides initiated a cascade of effects, beginning with increased availability of nitrogen and soil water, followed by increased growth of herbaceous vegetation. Response of butterflies and magnitudes of runoff and erosion closely followed herbaceous vegetation recovery. Effects on shrubs, biological soil crust, tree cover, surface woody fuel loads, and sagebrush-obligate bird communities will take longer to be fully expressed. In the short term, cool wet sites were more resilient than warm dry sites, and resistance was mostly dependent on pretreatment herbaceous cover. At least 10 yr of posttreatment time will likely be necessary to determine outcomes for most sites. Mechanical treatments did not serve as surrogates for prescribed fire in how each influenced the fuel bed, the soil, erosion, and sage-obligate bird communities. Woody vegetation reduction by any means resulted in increased availability of soil water, higher herbaceous cover, and greater butterfly numbers. We identified several trade-offs (desirable outcomes for some variables, undesirable for others), involving most components of the study system. Trade-offs are inevitable when managing complex natural systems, and they underline the importance of asking questions about the whole system when developing management objectives. Substantial spatial and temporal heterogeneity in sagebrush steppe ecosystems emphasizes the point that there will rarely be a ''recipe'' for choosing management actions on any specific area. Use of a consistent evaluation process linked to monitoring may be the best chance managers have for arresting woodland expansion and cheatgrass invasion that may accelerate in a future warming climate.

We tested the impact of P deficiency, K deficiency, and their interaction on seed alkaloid concentrations and profile, yield and mineral content in sweet (low-alkaloid) and bitter (high-alkaloid) varieties of narrow-leafed lupin (Lupinus angustifolius L.). P deficiency reduced seed alkaloid concentrations in sweet, but not in bitter, varieties. Under P deficiency, the alkaloid profile in harvested seed of sweet varieties mimicked that of the bitter variety Fest, with 13-hydroxylupanine dominating over lupanine. With adequate or abundant P, lupanine was the predominant alkaloid in sweet varieties. K deficiency was associated with an 8-fold increase of seed alkaloid concentrations in the sweet variety Danja (from 1000 to 8000 mg kg −1 DM), mostly due to the stimulation of lupanine production. There was a significant interaction between P and K that affected seed alkaloid concentrations in two ways: (i) the inhibitory effect of P deficiency was only apparent under K deficiency and (ii) the lowest seed alkaloid concentrations occurred with abundant K (240 mg K kg −1 ) and P (60 mg P kg −1 ). Seed yield of all varieties increased asymptotically with increasing P and reached a maximum at adequate P (30 mg P kg −1 ). There was no impact of K deficiency on seed yield. In sweet and bitter varieties P supply increased seed N, P and Zn concentrations, but not K. In contrast, seed K concentrations increased and P concentrations decreased with increasing K supply. These findings suggest that P fertiliser should be supplemented with K, to avoid high seed alkaloid concentrations stimulated by asymptomatic K deficiency at high P levels. * FAX No: +61-8-9387 8991.

The MspI restriction-modification system, which recognizes the sequence 5'-CCGG-3', has been previously cloned and sequenced (1). We subcloned the methyltransferase gene (M.MspI) downstream of the ptac promoter in the multicopy vector pUC119 and overexpressed it in E. coli. Upon induction with IPTG, M.MspI constitutes more than 10% of cellular protein. A scheme has been devised to purify large amounts of biologically active M.MspI to apparent homogeneity from these overexpressing E. coli cells. Approximately 0.8 mg of pure M.MspI per gram of cells (wet weight) can be obtained. The apparent molecular weight of M.MspI is 49 kD, by SDS gel electrophoresis and 48-54 kD by gel filtration. At low concentrations (less than 0.4 mg/ml), the methyltransferase is a monomer in solution but at higher concentrations (greater than 3.0 mg/ml) it exists predominantly as a dimer. Polyclonal antibodies raised against M.MspI cross-react with the DNA-methyltransferases of several other restricti...

This article addresses the distinct ethical challenges of action research in inter-organisational projects. Traditionally, the literature on action research has distinguished between two researcher roles: The problem-solver and the observer. Based on an action research project in a Danish inter-organisational network, a third role as legitimiser is identified as an ethical challenge. Potentially, the legitimacy that the researchers carry as academic knowledge-generating actors may be used by a particular company to involve other companies in the network. Thus, the researchers may be perceived as bringing into the other organisations a Trojan Horse containing the interests of this particular company. Lack of clarity in defining the role of the action researcher may thus jeopardise the trustworthiness of the researchers and the action research project. On the basis of the case study analysis, the article develops a number of preliminary points of ethical consideration for future research analysis.

Telemetry has allowed researchers to document the upstream migrations of anadromous fish in freshwater. In many anadromous alosine telemetry studies, researchers use downstream movements (''fallback'') as a behavioral field bioassay for adverse tag effects. However, these downstream movements have not been uniformly reported or interpreted. We quantified movement trajectories of radio-tagged anadromous alewives (Alosa pseudoharengus) in the Ipswich River, Massachusetts (USA) and tested blood chemistry of tagged and untagged fish held 24 h. A diverse repertoire of movements was observed, which could be quantified using (a) direction of initial movements, (b) timing, and (c) characteristics of bouts of coupled upstream and downstream movements (e.g., direction, distance, duration, and speed). Because downstream movements of individual fish were almost always made in combination with upstream movements, these should be examined together. Several of the movement patterns described here could fall under the traditional definition of ''fallback'' but were not necessarily aberrant. Because superficially similar movements could have quite different interpretations, post-tagging trajectories need more precise definitions. The set of metrics we propose here will help quantify tag effects in the field, and provide the basis for a conceptual framework that helps define the complicated behaviors seen in telemetry studies on alewives and other fish in the field.

Biochar addition to agricultural soil has been suggested to mitigate climate change through increased biogenic carbon storage and reduction of greenhouse gas emissions. We measured the fluxes of N2O, CO2, and CH4 after adding 9 t ha−1 biochar on an agricultural soil in Southern Finland in May 2009. We conducted these measurements twice a week for 1.5 months, between sowing and canopy closure, to capture the period of highest N2O emissions, where the potential for mitigation would also be highest. Biochar addition increased CH4 uptake (96% increase in the average cumulative CH4 uptake), but no statistically significant differences were observed in the CO2 and N2O emissions between the biochar amended and control plots. Added biochar increased soil water holding capacity by 11%. Further studies are needed to clarify whether this may help balance fluctuations in water availability to plants in the future climate with more frequent drought periods.▶ Biochar addition to boreal agricultural soil increases CH4 uptake. ▶ Biochar addition to boreal agricultural soil increases water holding capacity. ▶ Biochar addition to boreal agricultural soil had no effect on N2O or CO2 fluxes.

Pest control technology, developed for temperate countries was introduced into the Caribbean without any consideration for the fragility of the islands ecosystem. A signi®cant increase in the utilization of pesticides by banana farmers in St. Lucia occurred during recent years. The mobility of two commonly used pesticides,`ametryn' [N 2-ethyl-N 4-isopropyl-6-methylthio-1,3,5-triazine-2,4-diamine] and`pirimiphos-ethyl' [O-2-diethylamino-6-methylpyrimidin-4-yl O,O-diethyl phosphothiorate] on two different soils on banana cultivated hillsides in St. Lucia was studied. Ametryn and pirimiphos-ethyl were applied to both sites, and soil samples were collected at different time intervals and were analyzed using gas chromatography. At both sites and on both soil types, quite early in the season, both pesticides leached down to 0.4 m depth. However, there appeared to be equal or greater leaching and downslope transport of pesticides on hillside 2. Pesticide concentration showed a reducing trend with respect to time and depth in both soil types at both sites. However, because of runoff interference, the half-life of pirimiphos-ethyl could not be properly de®ned, but half-life for ametryn was estimated to be 3 to 8 days. The short half-life for ametryn indicates the fast degradation of this pesticide under tropical conditions which could reduce the risk of environmental pollution. The environmental mobility of both pesticides suggests that leaching of ametryn and pirimiphos-ethyl may, in some circumstances create surface and groundwater pollution problems.

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As expressed in the Ramsar Convention, the wise use of wetlands, including coastal lagoons, is one of the greatest environmental concerns across the globe. Seagrass beds are the key element for sustaining coastal lagoon ecosystems. Eutrophication, especially by nitrogen and phosphorus, has degraded many coastal waters and has been invoked as a major cause of seagrass disappearance worldwide. Seagrass had been used as fertilizer in Japan, and the removal of seagrass contributed to the decline of nutrients in the water. The shifts of primary producers from rooted macrophytes to phytoplankton occurred simultaneously between the mid-1950s and 1965 in Japanpresumably because of the wide use of herbicides for rice paddies. Increased phytoplankton induced the increase of fishery yield of clam on one hand and non-edible biofouling species on the other. Because a phytoplankton-dominated ecosystem is easily oxygen depleted at the bottom with the accumulation of organic matter of phytoplankton origin, preventing hypoxia is the key factor to maintain high secondary production for bivalve fisheries and sustainable use of the ecosystem of coastal lagoons.

We evaluated the bioavailability of Cd in 86 components of 57 jewelry items found to contain high levels of Cd (> 10,000 ppm) by X-ray fluorescence (XRF), using extractions that simulate mouthing or swallowing of jewelry items. Methods: We screened jewelry for Cd content by XRF. Bioavailability was measured in two ways. Items were placed in saline solution at 37°C for 6 hr to simulate exposures from mouthing of jewelry items. Items were placed in dilute hydrochloric acid (HCl) at 37°C for 6-96 hr, simulating the worst-case scenario of a child swallowing a jewelry item. Damaged pieces of selected samples were also extracted by both methods to determine the effect of breaching the outer plating on bioavailability. Total Cd content of all items was determined by atomic absorption. results: The 6-hr saline extraction yielded as much as 2,200 μg Cd, and 24-hr dilute HCl extraction yielded a maximum of > 20,000 μg Cd. Leaching of Cd in dilute HCl increased linearly over 6-96 hr, indicating potential for increasing harm the longer an item remains in the stomach. Damage to jewelry by breaching the outer plating generally, but not always, increased Cd release. Bioavailability did not correlate directly with Cd content. conclusions: These results indicate the potential for dangerous Cd exposures to children who wear, mouth, or accidentally swallow high-Cd jewelry items. key words: cadmium, children's health, import safety, jewelry, potential cadmium exposures.

Coralline algae are one of the most important constructors of biogenic habitats. In the Mediterranean Sea, the dominant coralline algae species form crusts comprising formations known as coralligène, considered as very important fishing grounds by fishermen. Due to the destructive effect of fishing gear activities over coralligène, these formations were recently protected from the use of active benthic gears by the EU 1967/2006 Mediterranean fisheries management Regulation. However, the lack of maps and information on their distribution makes the effective application of these measures impossible. The present publication contributes to the mapping of coralligène in the southern Aegean Sea (eastern Mediterranean), and to the study of coralline algae formation morphology, distribution, development conditions and relation to fisheries using a combination of single-beam echo sounder, sidescan sonar, sub-bottom profiler recordings and biological and sedimentological ground-truthing techniques. The coralligène formations were recognized as two distinct acoustic signatures of localized backscatter facies distinguishable from other hard substrate reflectors at depths ranging from 55.9 to 114.0 m, but mainly between 70 and 90 m. Two types of formations were identified: minute reefs 0.5-2.5 m in height and superficial layer formations no more than 0.2 m thick over the substrate. The seismic profiles revealed a cavernous internal structure of the minute reefs and recorded their development on both hard and soft substrates. The distribution of formations was contagious, creating aggregations. The finding of superficial layer formations and coralline shreds around minute coralligène reefs indicated that the former could be an intermediate development type between isolated small coralline pebbles, rhodoliths, and minute reefs. Regarding the development conditions, sidescan sonar imagery indicated that the optimal conditions for the establishment and development of coralligène formations are medium intensity currents. Concerning human activity over coralligène, trawl traces were recorded near but not over minute reefs and both near and crossing superficial layer type aggregations, while a submarine cable was also recorded among minute reefs. The mapping of coralligène aggregation areas is essential for the application of the EU Regulation and the protection of this important marine habitat.

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Biologists increasingly use marketing strategies to promote their results, obtain funding, and influence decisionmakers, but this development can compromise public perceptions of their objectivity and prevent the effective communication of reliable scientific knowledge. Responsible and effective communication is particularly important in this era of biotechnological innovation and global environmental change, when knowledge is often uncertain and rapidly evolving and can have huge consequences for society. Although scientists and science journalists carefully evaluate scientific results, they more freely choose rhetorical elements and, in particular, their metaphors, despite the value-laden judgments that often accompany these choices. We therefore argue that metaphors should be carefully chosen and evaluated alongside empirical evidence, because they shape data interpretation and how science influences society. Here, we propose guidelines for the responsible use of metaphors in science writing and communication.

As human influences fragment native communities and ecosystems, remaining land must be better managed to conserve many elements of biodiversity. Much of this land is privately held, yet traditional private land-use management practices often further diminish biodiversity by promoting favored or edge-adapted species.

An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna].

Factors influencing natural variability in coarse woody debris (CWD) as an indicator of ecosystem services in boreal forests need to be better defined. We analysed the CWD characteristics in 194 dynamic primeval boreal forest stands and 3 landscapes under different disturbance regimes. The volume of CWD in the spruce dominated forests linearly increased with increasing annual temperature. The CWD amount and species diversity were higher in spruce than in pine dominated stands. The CWD volume increased in relationship to the types of forest stand dynamics in the order: 'even-aged', 'cohort', 'fine-scale gap'. The CWD volumes were 52.3; 207.0 and 146.8 m 3 ha À1 and the dead:live wood volume ratios were 29%, 102% and 60% in the landscapes with disturbance regimes driven by periodic surface fires, cohort-replacing windthrow, and fine-scale gap dynamics, respectively. Mean dead:live wood volume ratios exceeded 100% in spruce stands with even-aged and cohort dynamics and in pine stands with even-aged and fine-scale gap dynamics. The CWD decay class diversity was higher in pine than in spruce dominated stands. The CWD volume distribution by decay class was the most even in forest stands driven by fine-scale gap dynamics in both spruce and pine dominated stands. The CWD position diversity was higher in spruce than in pine dominated forests. Fallen logs dominated among other CWD position types in the spruce dominated stands with cohort and fine-scale gap dynamics and in pine stands with cohort and even-aged dynamics. Pine forests with fine-scale gap dynamics stored the greatest volume of snags. In the spruce dominated stands, the proportion of leaning logs decreased and the proportion of snags and stumps increased among forest dynamic types in the following order: even-aged, cohort, fine-scale gap. The CWD diameter distribution had peaks in small-sized CWD in even-aged spruce stands and pine stands with fine-scale gap dynamics. Mid-sized CWD dominated in spruce stands driven by cohort and fine-scale gap dynamics and pine stands with even-aged and cohort dynamics. The large quantity of CWD that encompassed a wide range of variation in tree species, decay class, position type and size creates a diversity of CWD habitats for saproxylic organisms and ensures functional resilience in boreal forest ecosystems. Our results stress that mean annual temperatures and natural site-specific disturbance regimes should be taken into account when setting targets for CWD volumes and dead:live wood volume ratios for management and restoration of CWD in boreal forests.

In south-eastern Australia, the introduced Red Fox (Vulpes vulpes) is a major predator of native wildlife and livestock. Fox control in agricultural landscapes is heavily reliant on the laying of poisoned baits by private landholders, yet there have been few assessments of the application or success of landholder-baiting practices. We evaluated a community-based fox-baiting campaign, typical of programs employed throughout the agricultural regions of south-eastern Australia to control foxes. We recorded the spatial coverage of 1080 baits deployed by landholders, assessed baiting procedures, monitored the survival of six radio-collared foxes during and after baiting, and compared the spatial coverage and likely effectiveness of the baiting program with two alternative (theoretical) baiting strategies. Relative to other baiting programs, coordination among neighbours was reasonably high, with 37.5% of baited properties (n = 40) adjoining ‡3 neighbouring properties that also contained baits. Nevertheless, the maximum distance from the centre of a baited property to the nearest edge of an unbaited property was <750 m (mean = 380 m ± 147 m SD). On average, 33% (±17% SD) of each fox's home range overlapped with baited properties, but only two foxes died during the baiting program. The remaining four foxes were still alive 10 weeks after baiting ceased. Modelling of simulated fox home ranges showed that 13.5% contained no bait stations based on the community baiting program, whereas alternative roadside-and gridbaiting strategies (theoretically) delivered baits to all simulated home ranges. Some landholders employed practices that could reduce the effectiveness of baiting programs such as not removing decayed baits before deploying new ones or placing bait stations too close together. Our research illustrates the difficulties of managing a coordinated baiting program on private land that effectively controls foxes. Alternative baiting strategies such as roadside baiting need to be considered to improve fox control in agricultural landscapes.

This paper presents results from a survey of waste management authorities aimed at identifying the opportunities and constraints associated with implementing economic instruments (EIs) for solid waste management (SWM) in South Africa (SA). Almost all respondents felt that EIs could lead to reduced waste generation and increased diversion of waste from landfill to recycling, and that they should eventually be implemented in the field of SWM in SA, although opinions varied as to the appropriate timeframe for implementation. The general consensus was that a number of fundamentals had to be in place first, including promulgation of the pending Waste Management Bill, political will, education and awareness, capacity and infrastructure development, cost recovery in waste management practices, and enforcement of existing instruments, such as the Minimum Requirements for landfill design and operation. Furthermore, if and when EIs are implemented, institutional limitations must be taken into account in their selection, design and implementation.

We measured nitrous oxide (N 2 O), dinitrogen (N 2 ), methane (CH 4 ), and carbon dioxide (CO 2 ) fluxes in horizontal and vertical flow constructed wetlands (CW) and in a riparian alder stand in southern Estonia using the closed chamber method in the period from October 2001 to November 2003. The replicates' average values of N 2 O, N 2 , CH 4 and CO 2 fluxes from the riparian gray alder stand varied from −0.4 to 58 g N 2 O-N m −2 h −1 , 0.02-17.4 mg N 2 -N m −2 h −1 , 0.1-265 g CH 4 -C m −2 h −1 and 55-61 mg CO 2 -C m −2 h −1 , respectively. In horizontal subsurface flow (HSSF) beds of CWs, the average N 2 emission varied from 0.17 to 130 and from 0.33 to 119 mg N 2 -N m −2 h −1 in the vertical subsurface flow (VSSF) beds. The average N 2 O-N emission from the microsites above the inflow pipes of the HSSF CWs was 6.4-31 g N 2 O-N m −2 h −1 , whereas the outflow microsites emitted 2.4-8 g N 2 O-N m −2 h −1 . In VSSF beds, the same value was 35.6-44.7 g N 2 O-N m −2 h −1 . The average CH 4 emission from the inflow and outflow microsites in the HSSF CWs differed significantly, ranging from 640 to 9715 and from 30 to 770 g CH 4 -C m −2 h −1 , respectively. The average CO 2 emission was somewhat higher in VSSF beds (140-291 mg CO 2 -C m −2 h −1 ) and at the inflow microsites of HSSF beds (61-140 mg CO 2 -C m −2 h −1 ). The global warming potential (GWP) from N 2 O and CH 4 was comparatively high in both types of CWs (4.8 ± 9.8 and 6.8 ± 16.2 t CO 2 eq ha −1 a −1 in the HSSF CW 6.5 ± 13.0 and 5.3 ± 24.7 t CO 2 eq ha −1 a −1 in the hybrid CW, respectively). The GWP of the riparian alder forest from both N 2 O and CH 4 was relatively low (0.4 ± 1.0 and 0.1 ± 0.30 t CO 2 eq ha −1 a −1 , respectively), whereas the CO 2 -C flux was remarkable (3.5 ± 3.7 t ha −1 a −1 ). The global influence of CWs is not significant. Even if all global domestic wastewater were treated by wetlands, their share of the trace gas emission budget would be less than 1%.

Outdoor mesocosms (experimental drainage ditches) were treated repeatedly with linuron at nominal concentrations of 0, 0.5, 5, 15, and 50 g/L. After each of three treatments (with 4-week intervals), the systems were kept static for 1 week. Subsequently, they were flushed with nonpolluted surface water with a residence time of 5 d until the next treatment. Species composition and abundance of macrophytes, periphyton, phytoplankton, zooplankton, and macroinvertebrates were examined at prefixed time intervals. During the treatment periods, significant decreases in oxygen concentration and pH were observed, whereas the systems recovered during the flushing periods. The effects of the pulsed treatments on the structural endpoints (biota) were rarely significant and consistently were difficult to interpret. We conclude that under these experimental conditions, pulsed treatment with linuron causes only minor and negligible effects on the abundance of organisms in mesocosms, even when maximum permissible concentrations are exceeded by about 80 times. Risk assessment based on the more sensitive physiologic and functional endpoints suggested that the safety factor of 0.1 times the acute EC50 of the most sensitive standard alga (Scenedesmus acutus), as adopted in the Uniform Principles of the European Union, is sufficient to protect the community of the mesocosms in an exposure regime that was realistic for Dutch drainage ditches, using a photosynthesis inhibitor as the benchmark compound.

April 2016 sees the 30 th anniversary of the accident at the Chernobyl nuclear power plant. As a consequence of the accident populations were relocated in Belarus, Russia and Ukraine and remedial measures were put in place to reduce the entry of contaminants (primarily 134þ137 Cs) into the human food chain in a number of countries throughout Europe. Remedial measures are still today in place in a number of countries, and areas of the former Soviet Union remain abandoned. The Chernobyl accident led to a large resurgence in radioecological studies both to aid remediation and to be able to make future predictions on the post-accident situation, but, also in recognition that more knowledge was required to cope with future accidents. In this paper we discuss, what in the authors' opinions, were the advances made in radioecology as a consequence of the Chernobyl accident. The areas we identified as being significantly advanced following Chernobyl were: the importance of semi-natural ecosystems in human dose formation; the characterisation and environmental behaviour of 'hot particles'; the development and application of countermeasures; the "fixation" and long term bioavailability of radiocaesium and; the effects of radiation on plants and animals.

Mutations in human mitochondrial DNA (mtDNA) can cause mitochondrial disease and have been associated with neurodegenerative disorders, cancer, diabetes and aging. Yet our progress toward delineating the precise contributions of mtDNA mutations to these conditions is impeded by the limited availability of faithful transmitochondrial animal models. Here, we report a method for the isolation of mutations in mouse mtDNA and its implementation for the generation of a collection of over 150 cell lines suitable for the production of transmitochondrial mice. This method is based on the limited mutagenesis of mtDNA by proofreading-deficient DNA-polymerase γ followed by segregation of the resulting highly heteroplasmic mtDNA population by means of intracellular cloning. Among generated cell lines, we identify nine which carry mutations affecting the same amino acid or nucleotide positions as in human disease, including a mutation in the ND4 gene responsible for 70% of Leber Hereditary Optic ...

Carcharhinus sorrah (Mülle and Henle, 1839) is a coastal pelagic shark of the tropical and subtropical Indo–West Pacific, reaching 1.6 m total length. The species is widely harvested in line, net, and trawl fisheries over tropical continental shelves. We investigated mtDNA genetic differentiation in C. sorrah across the majority of the species&#39; range, and examined the importance of six major historical and contemporary biogeographic features in shaping population genetic structure in this species. The present study includes dense sampling for a shark species across the Indo–West Pacific, with 349 specimens sampled from 21 collection locations from the northwestern Indian Ocean, Southeast Asia, New Caledonia, and to southerly distribution limits in Australia. Based on 469 base pairs of the control region, we found extensive genetic population structure, with allopatric lineages confined to Australia, New Caledonia, and the remaining surveyed area. Significant genetic subdivisions...

Aquatic macroinvertebrates living in anastomosing lowland rivers use different habitats and respond differently to the hydrological regime. In this paper, the structure and composition of benthic, drifting and marginal macroinvertebrate assemblages are analyzed in the lowland river Ctalamochita (Córdoba, Argentina). The assemblages were studied in an annual cycle; a comparison among the composition of benthos, drift and marginal fauna was carried out; and size structure of the assemblages was characterized. Samples were obtained from two sites: a rural and an urban site. In total 73 taxa of aquatic macroinvertebrates were collected. Benthos was characterized by Chironomidae and Oligochaeta; marginal fauna was mainly constituted by Coleoptera, Heteroptera, Decapoda, the Trichoptera Nectopsyche sp., Ephemeroptera and Odonata. Drifting assemblage was composed by macroinvertebrates from local and remote upstream benthos, and from the marginal zone. Marginal fauna diversity was higher than benthos and drift. Total biomass of the assemblages pooled together was relatively equitably among size classes. Larger size classes consisted of organisms from the marginal zone whereas the smallest ones were composed by benthic and drifting organisms. In the study area there is habitat partitioning in the lateral dimension of the river. Marginal fauna was more diverse due to the asymmetry of transport and deposit processes, which generate a heterogeneous habitat in the bankside. The relation between fine substrate and high current velocity determines an unstable habitat in the central channel, which makes colonization by benthic macroinvertebrates difficult.

a b s t r a c t H.M. the King of Thailand proposed Bueng Makkasan, the repair factory belonging to the Royal Railway of Thailand (RTT), as a wastewater-collection pond of Bangkok City. It covers about 40 acres, with 5-m depth. The RRT wastewater pond functions at a repair factory and is the collection site of the directpolluted waste of homeless people living around the pond rim and also for temporary reservoir of two influent canals. The water hyacinth aquatic plants were grown well and covered almost the entire surface area of the pond.

Desert winds aerosolize several billion tons of soilderived dust each year, including concentrated seasonal pulses from Africa and Asia. These transoceanic and transcontinental dust events inject a large pulse of microorganisms and pollen into the atmosphere and could therefore have a role in transporting pathogens or expanding the biogeographical range of some organisms by facilitating long-distance dispersal events. As we discuss here, whether such dispersal events are occurring is only now beginning to be investigated. Huge dust events create an atmospheric bridge over land and sea, and the microbiota contained within them could impact downwind ecosystems. Such dispersal is of interest because of the possible health effects of allergens and pathogens that might be carried with the dust.

Due to widespread concern that menstruating women might be attacked by black bears (Ursus americanus), we recorded responses of 26 free-ranging black bears to tampons from 26 women and recorded responses of 20 free-ranging bears to 4 menstruating women in northeastern Minnesota. Menstrual odors were essentially ignored by black bears of all ages and either sex, regardless of season or the bear's reproductive status. In an extensive review of black bear attacks across North America, we found no instance of black bears attacking or being attracted to menstruating women.

Structural information on soil organic matter (SOM) at the molecular level can be obtained on diverse structural units that are amenable to degradation techniques. Chemolytic techniques in combination with colorimetric analyses or GC MS are used to determine amino acids (proteins), sugars (polysaccharides), lipids, or aromatic oxidation products from lignin or charred organic matter. Microbial markers (amino sugars, muramic acid) are analyzed after hydrolysis and gas chromatographic separation. Macromolecular structures can also be subjected to thermochemolytic degradation or pyrolysis and subsequent analysis of the fragments by GC MS. Alternative techniques for the examination of organic matter in heterogeneous macromolecular mixtures are non-destructive spectroscopic methods, such as nuclear magnetic resonance (NMR) spectroscopy. Although this technique can give good results concerning the gross chemical composition, speci®c compounds are hardly identi®ed. The combination of spectroscopic techniques with thermolytic and chemolytic methods will add substantially to the understanding of the nature of refractory soil organic matter. Physical fractionation prior to analysis provides a means to dierentiate between distinct SOM pools that can be further characterized by the methods described above. Studies on SOM structural characteristics have focused mainly on the A horizons of soils under agriculture and litter biodegradation in forest soils and need to be extended to a wider variety of soil types and the subsoil. #

Omnivory is an important interaction that has been the centre of numerous theoretical and empirical studies in recent years. Most of these studies examine the conditions necessary for coexistence between an omnivore and an intermediate consumer. Trait variation in ecological interactions (competition and predator tolerance) among intermediate consumers has not been considered in previous empirical studies despite the evidence that variation in species-specific traits can have important community-level effects. 2. I conducted a multifactorial microcosm experiment using species from the Sarracenia purpurea phytotelmata community, organisms that inhabit the water collected within its modified leaves. The basal trophic level consisted of bacterial decomposers, the second trophic level (intermediate consumers) consisted of protozoa and rotifers, and the third trophic level (omnivore) were larvae of the pitcher plant mosquito Wyeomyia smithii . Trophic level number (1, 2 and 3), resources (low and high), omnivore density (low and high) and intermediate consumer (monoculture of five protozoa and rotifers) identity were manipulated. Abundance of the basal trophic level, intermediate consumers, and growth of the omnivore were measured, as well as time to extinction (intermediate consumers) and time to pupation (mosquito larvae).

Plant litter and the microbial biomass are the major parent materials for soil organic matter (SOM) formation. Plant litter is composed of complex mixtures of organic components, mainly polysaccharides and lignin, but also aliphatic biopolymers and tannins. The composition and relative abundance of these components vary widely among plant species and tissue type. Whereas some components, such as lignin, are exclusively found in plant residues, speci®c products are formed by microorganisms, e.g. amino sugars. A wide variety of chemical methods is available for characterizing the chemical composition of these materials, especially the chemolytic methods, which determine individual degradation products and solid-state 13 C NMR spectroscopy, that gives an overview of the total organic chemical composition of the litter material. With the development of these techniques, an increasing number of studies are being carried out to investigate the changes during decay and the formation of humic substances. An overview is given on the amount of litter input, the proportion of various plant parts and their distribution (below-ground/above-ground), as well as the relative proportion of the different plant tissues. Major emphasis is on the organic chemical composition of the parent material for SOM formation and thus this paper provides information that will help to identify the changes occurring during biodegradation of plant litter in soils. q